Relational databases have been the dominant approach to store data for decades and they will probably be used for a very long time. However a lot of modern applications work with JSON, a format that does not fit naturally in a relational system.

NoSQL databases came to solve this problem and to improve the scalability of relational databases. NoSQL also allows working with data that change fast without having to change the database.

There are different types of NoSQL databases:

Document stores: MongoDB, Azure DocumentDB

Key/Value stores: Riak

Column stores: Cassandra

Big data analytics: HDInsight, Hadoop

The focus of this post is the document store offered by Microsoft: Azure DocumentDB.